Cached input
Repeated prompt prefixes are billed at OpenAI's reduced cached-input rate instead of the standard input rate.
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LLM API Pricing
OpenAI API Pricing in 2026
OpenAI bills GPT models per million tokens, with separate input and output rates. The table below lists OpenAI's official rates next to RunAPI's for each current GPT model — same API, same output, one key.
Updated June 18, 2026
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At a glance
What does the OpenAI API cost right now?
OpenAI bills per million tokens, with separate rates for input (your prompt) and output (the model's response). Output tokens cost more — the model has to generate each one. There is also a cheaper cached-input rate when you resend the same prompt prefix. All figures below are per million tokens.
Most popular
GPT-5.4 — the default choice for most production workloads.
Cheapest option
GPT-5.4-mini — the lower-priced option for high-volume work that does not need the flagship.
Maximum capability
GPT-5.5 — the most capable GPT model in the table, for complex reasoning and agent work.
Cache discount
Cached input tokens are billed at a fraction of the standard input rate.
Model-by-model breakdown
How much does each GPT model cost per million tokens?
The table shows official OpenAI pricing alongside RunAPI pricing from the current price list. Output tokens cost more than input tokens because generating each token takes more compute than reading it. No volume commits, no subscriptions.
| Model | Official input /M | Official output /M | RunAPI input /M | RunAPI output /M |
|---|---|---|---|---|
| gpt-5.5 Higher rate on long prompts | $5.00 | $30.00 | $4.00 20% OFF | $24.00 |
| gpt-5.4 Higher rate on long prompts | $2.50 | $15.00 | $2.00 20% OFF | $12.00 |
| gpt-5.4-mini | $0.75 | $4.50 | $0.60 20% OFF | $3.60 |
Cache and batch
How do cache and batch discounts cut your GPT bill?
OpenAI bills less for cached input tokens and cuts batch request costs in half for jobs that can wait up to 24 hours. Both matter if you're running a coding agent or processing large batches — repeated context and bulk work add up fast.
Batch API
OpenAI's Batch API bills jobs that can wait up to 24 hours at a lower rate than standard requests. See OpenAI's pricing page for the current batch rate.
Reasoning effort
GPT-5 models let you set reasoning effort. Lower effort emits fewer reasoning tokens, directly reducing output cost on metered billing.
Output token control
Cap max output tokens per request to bound cost and avoid runaway generations on long agentic tasks.
Provider comparison
Is the OpenAI API cheaper than Claude and Gemini?
Here is how the flagship models from OpenAI, Anthropic, and Google compare per million tokens at current prices. RunAPI gives you one API key that routes to all three.
| Provider | Flagship model | Input /M | Output /M | RunAPI rate |
|---|---|---|---|---|
| OpenAI | gpt-5.4 | $2.50 | $15.00 | $2.00 / $12.00 |
| Anthropic | claude-opus-4-7 | $5.00 | $25.00 | $4.00 / $20.00 |
| gemini-3.1-pro-preview | $2.00 | $12.00 | $1.60 / $9.60 |
Getting started
How to access the GPT API through RunAPI
1
Create a RunAPI account
Sign up and generate an API key from the dashboard.
2
Copy your API key
Go to Dashboard → API Keys. Create a key and save it — you will use this as your OpenAI API key.
3
Point your SDK to RunAPI
Set the base URL to https://runapi.ai/v1 and use your RunAPI key. Any OpenAI-compatible client works.
4
Start making requests
Use gpt-5.4, gpt-5.5, or any GPT model ID in the model parameter. RunAPI handles routing and bills at the rates listed on this page.
Frequently asked questions
OpenAI API Pricing FAQ
How much does the OpenAI GPT-5 API cost?
The pricing table above lists OpenAI's official rate and the RunAPI rate per million tokens for each GPT model. Both columns come from the current price list, so they match what you are billed.
Is there a free tier for the OpenAI API?
Creating an account and API key is free. API calls use prepaid, pay-as-you-go billing; add funds before making requests.
I'm building an n8n bot — how does API billing work for automation workflows?
Yes, and it works well for automation tools like n8n, Make, or Zapier. Each workflow step that calls a GPT model is billed by the tokens it uses — there is no separate per-call fee or rate limit tier. To estimate a recurring job, multiply its tokens by the rates in the pricing table.
How are image and audio inputs priced — it's not just tokens?
Image inputs are billed by tile — OpenAI divides the image into tiles and charges per tile. Audio is billed by duration. Neither uses the per-million-token unit shown in the pricing table.
Can I use the OpenAI SDK with RunAPI?
Yes. RunAPI is OpenAI-compatible. Point any OpenAI client at https://runapi.ai/v1, use your RunAPI key, and pass a GPT model ID. Existing code that already uses the OpenAI SDK works without any changes beyond the base URL and key, so migrating an established project takes about a minute.
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Run GPT-5 with one API key.
Create a free RunAPI account, get your API key, and call any OpenAI GPT model at the rates listed on this page.